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Author (up) Kroug, M.; Cherednichenko, S.; Choumas, M.; Merkel, H.; Kollberg, E.; Hübers, H.-W.; Richter, H.; Loudkov, D.; Voronov, B.; Gol'Tsman, G.
Title HEB quasi-optical heterodyne receiver for THz frequencies Type Conference Article
Year 2001 Publication Proc. 12th Int. Symp. Space Terahertz Technol. Abbreviated Journal
Volume Issue Pages 244-252
Keywords HEB mixer, NbN, MgO, conversion gain bandwidth, noise temperature
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Corporate Author Thesis
Publisher Place of Publication San Diego, CA, USA Editor
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Notes Approved no
Call Number Serial 319
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Author (up) Loudkov, D.; Khosropanah, P.; Cherednichenko, S.; Adam, A.; MerkeI, H.; Kollberg, E.; Gol'tsman, G.
Title Broadband fourier transform spectrometer (FTS) measurements of spiral and double-slot planar antennas at THz frequencies Type Conference Article
Year 2002 Publication Proc. 13th Int. Symp. Space Terahertz Technol. Abbreviated Journal Proc. 13th Int. Symp. Space Terahertz Technol.
Volume Issue Pages 373-369
Keywords NbN HEB mixers
Abstract The direct responses of NbN phonon-cooled hot electron bolometer (HEB) mixers, integrated with different planar antennas, are measured, using Fourier Transform Spectrometer (F1S). One spiral antenna and several double slot antennas, designed for 0.6, 1.4, 1.6, 1.8 and 2.5 THz central frequencies, are investigated. The Optimization of the measurement set-up is discussed in terms of the beam splitter and the F11S-to-HEB coupling. The result shows that the spiral antenna is circular polarized and has a bandwidth of about 2 THz. The frequency bands of double slot antennas show some shift from the design values and their relative bandwidth increases by increasing the design frequency. The antenna responses do not depend on the HEB bias point and temperature, as long as the device is in the resistive state.
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Notes Approved no
Call Number Serial 1530
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Author (up) Loudkov, D.; Tong, C. Y. E.; Blundell, R.; Kaurova, N.; Grishina, E.; Voronov, B.; Gol'tsman, G.
Title An investigation of the performance of the superconducting HEB슠mixer as a function of its RF슠embedding impedance Type Journal Article
Year 2005 Publication IEEE Trans. Appl. Supercond. Abbreviated Journal
Volume 15 Issue 2 Pages 472-475
Keywords HEB mixer
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Corporate Author Thesis
Publisher IEEE Place of Publication Editor
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Notes Approved no
Call Number Serial 371
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Author (up) Loudkov, D.; Tong, C.-Y. E.; Blundell, R.; Kaurova, N.; Grishina, E.; Voronov, B.; Gol’tsman, G.
Title An investigation of the performance of the superconducting HEB mixer as a function of its RF embedding impedance Type Journal Article
Year 2005 Publication IEEE Trans. Appl. Supercond. Abbreviated Journal IEEE Trans. Appl. Supercond.
Volume 15 Issue 2 Pages 472-475
Keywords waveguide NbN HEB mixers
Abstract We have conducted an investigation of the optimal embedding impedance for a waveguide superconducting hot-electron bolometric (HEB) mixer. Three mixer chip designs for 800 GHz, offering nominal embedding resistances of 70 /spl Omega/, 35 /spl Omega/, and 15 /spl Omega/, have been developed. We used both High Frequency Structure Simulator (HFSS) software and scale model impedance measurements in the design process. We subsequently fabricated HEB mixers to these designs using 3-4 nm thick NbN thin film. Receiver noise temperature measurements and Fourier Transform Spectrometer (FTS) scans were performed to determine the optimal combination of embedding impedance and normal-state resistance for a 50 Ohm IF load impedance. A receiver noise temperature of 440 K was measured at a local oscillator frequency 850 GHz for a mixer with normal state resistance of 62 /spl Omega/ incorporated into a circuit offering a nominal embedding impedance of 70 /spl Omega/. We conclude from our data that, for low noise operation, the normal state resistance of the HEB mixer element should be close to the embedding impedance of the mixer mount.
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Notes Approved no
Call Number 1439677 Serial 1464
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Author (up) Loudkov, D.; Tong, C.-Y. E.; Marrone, D. P.; Ryabchun, S.; Paine, S. N.; Blundell, R.
Title Transmission measurements of infrared filters for low-noise terahertz receiver applications Type Conference Article
Year 2005 Publication Proc. 16th Int. Symp. Space Terahertz Technol. Abbreviated Journal Proc. 16th Int. Symp. Space Terahertz Technol.
Volume Issue Pages 354-357
Keywords FTS, Zitex, alkali halide, crystalline quartz, Parylene, polyethylene, IR filters, transmission, THz applications
Abstract Infrared (IR) filters are very important to the efficient operation of cryogenic receivers. Usually, such filters are mounted on the radiation shield of the cryostat to reduce the heat load to the 4 K stage. Insufficient filtering may cause the temperature of the mixing element in a receiver to be excessively warm, leading to degradation in sensitivity. These filters should be effective in blocking the room temperature IR radiation from outside the cryostat, yet should be transparent across the desired signal frequency band. In the Terahertz frequency range, which is close to the infrared, it is difficult to find an inexpensive low- loss material that can provide the required IR blocking capacity. We present transmission measurements, made using a Fourier Transform Spectrometer (FTS), of a number of potential infrared filters between 0.4 and 1.6 THz. The filters tested include the widely-used, Teflon-based, Zitex-A and Zitex-G films, alkali halide based infrared filter, and crystalline quartz coated with Parylene, and polyethylene films.
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Notes Approved no
Call Number Serial 1473
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